The present invention relates to a battery pack, and more particularly, to a battery pack including a compact controller for controlling current flow.
Japanese Laid-Open Patent Publication No. 2002-190288 discloses a battery pack including a battery group of a plurality of rectangular batteries arranged in parallel configuration. The batteries are integrally held in a restrained state between two end plates, which are connected to each other. A controller controls the current flow when the battery group is charged and discharged. In the battery pack, the controller is arranged at one end of the battery group.
As shown in FIG. 1, the conventional controller 30 in the battery pack includes control devices such as cathode and anode main relays 31 and 32, a pre charge relay 33, and a resistor 34, each of which are spaced from each other and attached to the bottom surface of a case 35 for the controller 30. In FIG. 1, vibration absorption members 31a and 32a are respectively attached to the bottom surface of the main relays 31 and 32. A battery group 40 includes a plurality of batteries arranged in parallel configuration. The batteries are integrally held between two end plates 40a. Two connection cables 41 respectively connect the main relays 31 and 32 with a common cathode terminal and common anode terminal of the battery group 40. Two connection cables 42 connect the main relays 31 and 32 with an inverter of a vehicle.
Furthermore, a battery electronic control unit (ECU) 36 includes a communication connector 36a for communicating with an electronic control unit in the vehicle (vehicle ECU). The communication connector 36a is directly attached to the side surface of the case 35 facing toward an outlet 35a formed in the side surface of the case 35. The ECU 36 is connected to the vehicle ECU by the communication connector 36a and a signal wire harness 37. Part of the signal wire harness 37 extends out of the case 35. A side cover 38 covers the signal wire harness 37 located outside the case 35 so that the harness 37 cannot be accessed and to function as an electromagnetic shield. The side cover 38 is attached to an upper cover of the case 35, as shown by the phantom lines in FIG. 1.
However, in the conventional controller 30 shown in FIG. 1, space for installing each of the control devices 31 to 34 must be provided in the case 35. Furthermore, each of the control devices 31 to 34 can only be arranged along a place because of the difficulty in forming the case 35, which is made of steel plates, with a complicated shape. Therefore, a large space is required for the controller 30. Further, space for the signal wire harness 37 from the case 35 is necessary to prevent the signal wire harness 37 from being damaged by the edges of the case 35, and the signal wire harness 37 must be covered by a crimped or corrugated tube. This increases the necessary space and cost. Moreover, the controller 30 cannot have a large dimension in a direction perpendicular to the parallel configuration direction of the batteries. Thus, dimension B of the case 35 taken in the parallel configuration direction of the batteries in the battery group 2 is large. In this manner, a large space is necessary to install the battery pack, and it is difficult to save space with the conventional controller 30.
In the conventional controller 30, the side cover 38 covering the signal wire harness 37 of the ECU 36 must be attached to the upper cover of the case 35. This further increases costs. Further, a measure for coping with the edges of the steel plate of the case 35 is necessary at locations of the case 35 where the signal wire harness 37 is inserted. This also increases costs.